I'll take a stab at some of the question and maybe someone else will
chime in with additional info.
As you've probably noticed from a couple of the responses, there was
some uncertainty whether you were talking about the SIM, which makes you
telephone work, and the SD, on which you can store software and data of
your own choosing.
The SD is like a removable disk drive - serves the same purpose as a
removable hard drive, floppy, or USB Flash drive.
The SIM contains all the information the phone needs to connect to
your telephone company -- your account information, whether the phone
can be used for long distance calls, or even any non-emergency calls.
It's got information the phone company uses to identify you can keep
track of your usage so you can be billed.
That last is why you might want to switch SIM in another country.
For instance, I am a Cingular/ATT customer. My phone will work just
dandy in Europe with the same SIM that works in the U.S.
BUT - Cingular will charge me exhorbitant prices to call, partly
because the telephone doesn't have any idea where it is. The phone
companies know I'm in France, but the phone system, based on the
Cingular SIM, thinks it's back home, and every call I make is on a
foreign system, making long-distance calls.
However, if I buy a SIM there, my calls can be local, or at least
more local than if they try, on the basis of the account information
stored in my U.S. SIM, to make a call that starts out being a very long
distance from my home in Pennsylvania.
So, you may find it cheaper to use one SIM in Mexico and another in
the U.S. I've not been to Mexico with my phone, but I have been to
France, and the rates were a lot lower with a French SIM than they would
have been using my U.S. SIM in France.
Anyone else want to pop in?
[EMAIL PROTECTED] wrote:
> What type of data exactly is on a SIM card? And what is the difference
> between the "SIM Book" as opposed to the main phone book listings? I
> have heard that different SIM cards may/may not be needed for use in
> other countries but that is about all I know about them. I am
> currently in Mexico and the original Treo 680/Cingular GSM card in the
> phone works fine here for everything except caller ID. Just trying to
> learn more about these cards.
> Thanks,
> Dick Johnson
> ---------------------------------------
> Richard E. Johnson, MD
> [EMAIL PROTECTED]
> Treo 680
> Macintosh(es)
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
--
/"Thirty-five million deaths leave an empty place at only one family
table." /
(News commentator Eric Severied in a radio essay on the 25th
anniversary of the start of World War Two. 8/31/64)
[Non-text portions of this message have been removed]
